Aircraft: WIDEBODY; LOW WING; 2 TURBOJET ENG
Phase of flight: Taxi
Anomaly: Deviation / Discrepancy - Procedural Published Material / Policy; Ground Event / Encounter Other / Unknown

The other day I did two flights into SJU. On each with the [widebody aircraft] the ramp was not using SOP signals parking the aircraft and both times the aircraft was off the center line not inches but by 3 feet. I advocated and stopped the aircraft twice because I knew from reference points that the aircraft was not on the center line. The rampers parking the aircraft work for a third party. I called the duty manager asking for a bulletin or alert about the taxi lines and the parking procedures. I felt compelled to call the duty manager; I explained the operation to him and the Non-SOP activity on the ramp. I stated that the wing walkers and guide men are in position but are 'static' and detached from the operation. My example is the nose wheel of the aircraft 3 feet to the left of the center line and the left engine very close to the gate. They had no idea and were not aware of the errors. My statement to the duty manager on the 2 hour sit was that someone is going to hit something here with [this large an aircraft]..The second problem in SJU is the Airport taxi lines. We will exit runway 10 via H5 then make a left turn onto November and use the Apron to taxi to a gate. This is the first error. [This aircraft] should use a different gate for the reason of taxi and confined space. The taxi line on the apron IS NOT a wide body line and the crew must taxi 3-4 feet to the inside of the taxi line or the gear will be on the taxi lights and or in soft asphalt. I suggested to the duty manager in my call that company safety inspect the operation as I believe there is potential for an incident. The ramp apron is not suitable unless the aircraft is towed in to the gate. You're asking pilots to go against their training and not taxi on the yellow taxi line. Compounding the problem of being off the standard taxi line is improper hand signals and non SOP compliance by the ground crew parking the aircraft.The last issue in SJU with the [widebody aircraft] is the use of H to taxi to Runway 8 for takeoff. The airport issued us clearance to taxi on hotel to runway 8. The problem is the notes and the operation. The note on the plate indicated H is closed to AC with wingspan over 160 ft. SJU ground advises you to push deep beyond H3 then they taxi you on H between 10/8 to N1 left turn on the apron because S is closed. Ground assigns a follow me car that drives ahead of you 50-100 feet but no one is watching your wing. I even stated on the ground frequency that I needed a wing walker or the car to observe my left wing not in front of me. We were able to signal to a ramper working a commuter and he gave us a thumbs up or I would not have felt comfortable continuing. The other problem once past the commuter operation you pass many corporate aircraft on the ramp. If one is parked nose in it very possible you would strike its tail with the wing. I believe the company needs to do a safety assessment of the operation of the [widebody aircraft] on the ground; including taxi routes; parking areas; guidance sops (third party contractors) and special NOTAMs for the operation.Last but not least is while debarking the aircraft I noticed (the third party cleaning employees) all congregate in the loading bridge with all the new restocking and cleaning supplies while the passengers are debarking; the loading bridge goes from 7 feet wide to 24 inches. The pillow bags are 2 x 4 and they put about 6 against the wall plus 11 cleaners all stand in the debarking area and block the aircraft exit. They need to wait down stairs on the ramp until the aircraft is totally emptied. The handicap and elderly passengers really have a hard time exiting the aircraft normally let alone having the area size reduced to less than a third because 11-13 people want to stand on the loading bridge. They complicate the off-loading of the passengers tremendously. Widebody Air Carrier Captain reported that contract employees were not following SOP during taxi into the gate; creating a possible conflict with the jet bridge. He also believed that taxi routes assigned by ATC at SJU did not provide sufficient wingtip clearance and violated a note on the taxi diagram limiting weight and wingspan.